The present disclosure relates to invert emulsion fluids for use in subterranean operations, and, more specifically, to invert emulsion fluids for treating a portion of a subterranean formation.
Oil and gas hydrocarbons are naturally occurring in some subterranean formations. It is often desirable to treat at least a portion of a subterranean formation with a treatment fluid, such as a packer fluid, during hydrocarbon production. Packer fluids include liquids which are pumped into an annular opening between a casing and a wellbore wall or between adjacent, concentric strings of pipe extending into a wellbore. Packer fluids are useful for, among other things, the containment of reservoirs via hydrostatic pressure, reduction of the pressure gradient between the wellbore wall and casing to prevent wellbore collapse, and protection of metals and elastomers in wellbore conduits. In certain operations, packer fluids are used to contact a packer, such as a swellable packer or bridge plug, and can also be used for sand control, gravel packing, and workover operations.
Packer fluids are desirably compatible with the subterranean formation and possess specific mass and rheology sufficient to exert a hydrostatic pressure greater than the static pressure of the subterranean formation. It is further advantageous in many operations for packer fluids to be gellable, viscous, insulative, pumpable at low temperatures, and environmentally benign.
Conventionally, low rheology invert emulsion treatment fluids are used for, for example, deepwater drilling at cold temperatures (typically about 40° F.). Thinners are typically added to an invert emulsion treatment fluid for use in deepwater cold temperatures (typically about 40° F.), to prevent a substantial increase in the rheology of the fluid. Low rheology, however, limits the ability of treatment fluids to “pack” and/or to clean the borehole and suspend barite and drill cuttings.
Some of the desirable properties of an invert emulsion treatment fluid include good rheology, low plastic viscosity, high yield point, and high low-shear yield point. Preferably, an invert emulsion fluid is gellable, has a good shear strength, is stable, and has a suitable sag factor.
While embodiments of this disclosure have been depicted and described and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.